Glass substrate for a display

Abstract

A glass substrate for a display, which has a strain point of at least 550° C., an average linear expansion coefficient of from 65x10-7 to 100x10-7/°C. within a range of from 50 to 350° C. and a ratio KIC/d of at least 280 Pa.kg.m7/2 where KIC is the fracture toughness and d is the density.

What is claimed is:  
     
       1. A glass substrate for a display, which has 
       a strain point of at least 550° C.,  
       an average linear expansion coefficient of from 65×10 −7  to 100×10 −7 /°C. within a range of from 50 to 350° C. and  
       a ratio K IC /d of at least 280 Pa·kg·m 7/2  wherein K IC  is the fracture toughness and d is the density, which consistent essentially of  
       
         
           
                 
                 
                 
                 
               
                     
                     
                 
                     
                   SiO 2   
                   45 to 70 
                   wt %, 
                 
                     
                   Al 2 O 3   
                   2 to 20 
                   wt %, 
                 
                     
                   B 2 O 3   
                   0 to 6 
                   wt %, 
                 
                     
                   MgO 
                   1 to 10 
                   wt %, 
                 
                     
                   CaO 
                   1 to 10 
                   wt %, 
                 
                     
                   SrO 
                   0 to 9 
                   wt %, 
                 
                     
                   BaO 
                   0 to 9 
                   wt %, 
                 
                     
                   MgO + CaO + SrO + BaO 
                   10 to 25 
                   wt %, 
                 
                     
                   ZnO 
                   0 to 5 
                   wt %, 
                 
                     
                   Na 2 O + K 2 O 
                   5 to 15 
                   wt %, 
                 
                     
                   Li 2 O 
                   0 to 2 
                   wt %, and 
                 
                     
                   ZrO 2   
                   0 to 10 
                   wt %. 
                 
                     
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
     
     
       2. The glass substrate for a display according to  claim 1 , which has an average linear expansion coefficient of from 75×10 −7  to 95×10 −7 /°C. 
     
     
       3. The glass substrate for a display according to  claim 1 , which consists essentially of: 
       
         
           
                 
                 
                 
                 
               
                     
                     
                 
                     
                   SiO 2   
                   45 to 65 
                   wt %, 
                 
                     
                   Al 2 O 3   
                   6 to 20 
                   wt %, 
                 
                     
                   B 2 O 3   
                   0.5 to 6 
                   wt %, 
                 
                     
                   MgO 
                   2 to 5 
                   wt %, 
                 
                     
                   CaO 
                   1 to 10 
                   wt %, 
                 
                     
                   SrO 
                   0 to 6.5 
                   wt %, 
                 
                     
                   BaO 
                   0 to 2 
                   wt %, 
                 
                     
                   MgO + CaO + SrO + BaO 
                   10 to 17 
                   wt %, 
                 
                     
                   ZnO 
                   0 to 5 
                   wt %, 
                 
                     
                   Na 2 O + K 2 O 
                   5 to 15 
                   wt %, 
                 
                     
                   Li 2 O 
                   0 to 2 
                   wt %, and 
                 
                     
                   ZrO 2   
                   0 to 7 
                   wt %.